Sanitary Tissue Products Comprising a Surface Pattern

ABSTRACT

Sanitary tissue products having a surface pattern for better wet properties and/or cleaning properties.

FIELD OF THE INVENTION

The present invention relates to surface patterns utilized on sanitarytissue products, and more particularly to sanitary tissue productscomprising surface patterns, for example a 3D patterns, which can beformed for example by embossing the sanitary tissue product or fibrousstructure employed therein with the surface pattern and/or molding thesurface pattern into the sanitary tissue products and/or fibrousstructures, such as by wet molding and dry molding onto a molding membercomprising the surface pattern.

BACKGROUND OF THE INVENTION

Surface patterns having repeating design elements have been used onsanitary tissue products for many years. Most surface patterns have beencreated by embossing a pattern into a surface of the sanitary tissueproduct. Some have been created by wet forming, such as molding anembryonic fibrous structure onto a belt comprising a three-dimensionalresin pattern that gets imparted to a surface of a fibrous structure andultimately the sanitary tissue product formed from the fibrousstructure.

In the past, as shown in prior art FIGS. 1 and 2, an example of asanitary tissue product 10 comprises a surface pattern 12 on a surface14 of the sanitary tissue product 10. The surface pattern 12 comprised aset of lines 16 comprising a plurality of discrete depressions 18, suchas dots and/or dashes, which may be embossments and/or may be wetformed. The discrete depressions 18 were of generally the same size longthe length of the lines 16. Further, the set of lines 16 were arrangedsuch that a node 20 was formed between the lines 16. A single or doublerhombus element 22 was positioned within the node 20.

Consumers of sanitary tissue products, for example paper towels, thatcomprised surface patterns such as those shown in FIGS. 1 and 2, stilldesired sanitary tissue products that convey better wet propertiesand/or wet usage and/or better cleaning, such as soil removal and/orsoil dislodging, than prior sanitary tissue products.

Therefore, the problem faced by formulators is how to make a sanitarytissue product, for example a paper towel, having a surface pattern thatconveys better wet properties and/or wet usage and/or better cleaning,such as soil removal and/or soil dislodging, than known surface patternson sanitary tissue products.

Accordingly, there is a need for a sanitary tissue product comprising asurface pattern that conveys better wet properties (i.e., the papertowel does not fail as readily when insulted with water compared toknown sanitary tissue products) and/or wet usage and/or better cleaning,such as soil removal and/or soil dislodging, than existing sanitarytissue products.

SUMMARY OF THE INVENTION

The present invention fulfills the need described above by providing anovel surface pattern on a sanitary tissue product's surface.

The solution to the problem described above is to make a surface patternthat comprises a set of lines of a plurality of variable-sized discretedepressions, for example dot depressions of varying sizes, with and/orwithout a geometric shape, such as a rhombus element, positioned betweenthe set of lines, wherein the variable-sized discrete depressions arearranged in a periodic sequence based on the size of the discretedepressions such that the surface pattern that conveys better wetproperties and/or wet usage and/or better cleaning, such as soil removaland/or soil dislodging, than known surface patterns on sanitary tissueproducts.

In one example of the present invention, a sanitary tissue productcomprising a surface pattern having a repeating design element, whereinthe repeating design element contains a first geometric shape, forexample a first rhombus element, having a larger dimension and a smallerdimension such that it exhibits an aspect ratio of greater than 1.25,wherein the first geometric shape is positioned between a first set oftwo lines formed by a plurality of variable-sized discrete depressions,wherein the variable-sized discrete depressions are arranged in aperiodic sequence based on the size of the discrete depressions, whereinthe two lines are symmetrical to one another along the rhombus element'slargest dimension, is provided.

In still another example of the present invention, a method for making asanitary tissue product of the present invention, the method comprisingthe step of imparting, for example by embossing and/or molding, asurface pattern according to the present invention to a surface of afibrous structure and/or sanitary tissue product, is provided.

Accordingly, the present invention provides a sanitary tissue productcomprising a surface pattern according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a prior art surface pattern;

FIG. 2 is an image a sanitary tissue product comprising the prior artsurface pattern of FIG. 1;

FIG. 3 is a schematic representation of an example of a repeating designelement of a surface pattern according to the present invention;

FIG. 4 is a schematic representation of another example of a repeatingdesign element of a surface pattern according to the present invention;

FIG. 5 is a schematic representation of another example of a repeatingdesign element of a surface pattern according to the present invention;

FIG. 6 is a schematic representation of an example of a sanitary tissueproduct comprising a surface pattern according to the present invention;

FIG. 7 is a schematic representation of an example of a sanitary tissueproduct comprising a surface pattern according to the present invention;

FIG. 8 is a schematic representation of an example of a sanitary tissueproduct comprising a surface pattern according to the present invention;and

FIG. 9 is a schematic representation of an example of a sanitary tissueproduct comprising a surface pattern according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION Definitions

“Sanitary tissue product” as used herein means a soft, low density (i.e.<about 0.15 g/cm³) sanitary tissue product useful as a wiping implementfor post-urinary and post-bowel movement cleaning (toilet tissue), forotorhinolaryngological discharges (facial tissue), multi-functionalabsorbent and cleaning uses (absorbent towels also referred to as papertowels) and wet and dry wipes. The sanitary tissue product may beconvolutedly wound upon itself about a core or without a core to form asanitary tissue product roll. Alternatively, the sanitary tissue productmay be in the form of discrete sheets.

The sanitary tissue products and/or fibrous structures of the presentinvention may exhibit a basis weight of greater than 15 g/m² (9.2lbs/3000 ft²) to about 120 g/m² (73.8 lbs/3000 ft²) and/or from about 15g/m² (9.2 lbs/3000 ft²) to about 110 g/m² (67.7 lbs/3000 ft²) and/orfrom about 20 g/m² (12.3 lbs/3000 ft²) to about 100 g/m² (61.5 lbs/3000ft²) and/or from about 30 (18.5 lbs/3000 ft²) to 90 g/m² (55.4 lbs/3000ft²). In addition, the sanitary tissue products and/or fibrousstructures of the present invention may exhibit a basis weight betweenabout 40 g/m² (24.6 lbs/3000 ft²) to about 120 g/m² (73.8 lbs/3000 ft²)and/or from about 50 g/m² (30.8 lbs/3000 ft²) to about 110 g/m² (67.7lbs/3000 ft²) and/or from about 55 g/m² (33.8 lbs/3000 ft²) to about 105g/m² (64.6 lbs/3000 ft²) and/or from about 60 (36.9 lbs/3000 ft²) to 100g/m² (61.5 lbs/3000 ft²).

The sanitary tissue products of the present invention may exhibit adensity of less than about 0.60 g/cm³ and/or less than about 0.30 g/cm³and/or less than about 0.20 g/cm³ and/or less than about 0.10 g/cm³and/or less than about 0.07 g/cm³ and/or less than about 0.05 g/cm³and/or from about 0.01 g/cm³ to about 0.20 g/cm³ and/or from about 0.02g/cm³ to about 0.10 g/cm³.

The sanitary tissue products of the present invention may be in the formof sanitary tissue product rolls. Such sanitary tissue product rolls maycomprise a plurality of connected, but perforated sheets of fibrousstructure, that are separably dispensable from adjacent sheets.

The sanitary tissue products of the present invention may compriseadditives such as softening agents such as silicones and quaternaryammonium compounds, temporary wet strength agents, permanent wetstrength agents, bulk softening agents, lotions, silicones, wettingagents, latexes, especially surface-pattern-applied latexes, drystrength agents such as carboxymethylcellulose and starch, and othertypes of additives suitable for inclusion in and/or on sanitary tissueproducts.

“Fibrous structure” as used herein means a structure that comprises oneor more filaments and/or fibers. In one example, a fibrous structureaccording to the present invention means an orderly arrangement offilaments and/or fibers within a structure in order to perform afunction. Non-limiting examples of fibrous structures of the presentinvention include paper, fabrics (including woven, knitted, andnon-woven), and absorbent pads (for example for diapers or femininehygiene products).

Non-limiting examples of processes for making fibrous structures includeknown wet-laid papermaking processes and air-laid papermaking processes.Such processes typically include steps of preparing a fiber compositionin the form of a suspension in a medium, either wet, more specificallyaqueous medium, or dry, more specifically gaseous, i.e. with air asmedium. The aqueous medium used for wet-laid processes is oftentimesreferred to as a fiber slurry. The fibrous slurry is then used todeposit a plurality of fibers onto a forming wire or belt such that anembryonic fibrous structure is formed, after which drying and/or bondingthe fibers together results in a fibrous structure. Further processingthe fibrous structure may be carried out such that a finished fibrousstructure is formed. For example, in typical papermaking processes, thefinished fibrous structure is the fibrous structure that is wound on thereel at the end of papermaking, and may subsequently be converted into afinished product, e.g. a sanitary tissue product.

The fibrous structures of the present invention may be homogeneous ormay be layered. If layered, the fibrous structures may comprise at leasttwo and/or at least three and/or at least four and/or at least fivelayers.

The fibrous structures of the present invention may be co-formed fibrousstructures.

“Co-formed fibrous structure” as used herein means that the fibrousstructure comprises a mixture of at least two different materialswherein at least one of the materials comprises a filament, such as apolypropylene filament, and at least one other material, different fromthe first material, comprises a solid additive, such as a fiber and/or aparticulate. In one example, a co-formed fibrous structure comprisessolid additives, such as fibers, such as wood pulp fibers, andfilaments, such as polypropylene filaments.

“Solid additive” as used herein means a fiber and/or a particulate.

“Particulate” as used herein means a granular substance or powder.

“Fiber” and/or “Filament” as used herein means an elongate particulatehaving an apparent length greatly exceeding its apparent width, i.e. alength to diameter ratio of at least about 10. In one example, a “fiber”is an elongate particulate as described above that exhibits a length ofless than 5.08 cm (2 in.) and a “filament” is an elongate particulate asdescribed above that exhibits a length of greater than or equal to 5.08cm (2 in.).

Fibers are typically considered discontinuous in nature. Non-limitingexamples of fibers include wood pulp fibers and synthetic staple fiberssuch as polyester fibers.

Filaments are typically considered continuous or substantiallycontinuous in nature. Filaments are relatively longer than fibers.Non-limiting examples of filaments include meltblown and/or spunbondfilaments. Non-limiting examples of materials that can be spun intofilaments include natural polymers, such as starch, starch derivatives,cellulose and cellulose derivatives, hemicellulose, hemicellulosederivatives, and synthetic polymers including, but not limited topolyvinyl alcohol filaments and/or polyvinyl alcohol derivativefilaments, and thermoplastic polymer filaments, such as polyesters,nylons, polyolefins such as polypropylene filaments, polyethylenefilaments, and biodegradable or compostable thermoplastic fibers such aspolylactic acid filaments, polyhydroxyalkanoate filaments andpolycaprolactone filaments. The filaments may be monocomponent ormulticomponent, such as bicomponent filaments.

In one example of the present invention, “fiber” refers to papermakingfibers. Papermaking fibers useful in the present invention includecellulosic fibers commonly known as wood pulp fibers. Applicable woodpulps include chemical pulps, such as Kraft, sulfite, and sulfate pulps,as well as mechanical pulps including, for example, groundwood,thermomechanical pulp and chemically modified thermomechanical pulp.Chemical pulps, however, may be preferred since they impart a superiortactile sense of softness to tissue sheets made therefrom. Pulps derivedfrom both deciduous trees (hereinafter, also referred to as “hardwood”)and coniferous trees (hereinafter, also referred to as “softwood”) maybe utilized. The hardwood and softwood fibers can be blended, oralternatively, can be deposited in layers to provide a stratified web.U.S. Pat. No. 4,300,981 and U.S. Pat. No. 3,994,771 are incorporatedherein by reference for the purpose of disclosing layering of hardwoodand softwood fibers. Also applicable to the present invention are fibersderived from recycled paper, which may contain any or all of the abovecategories as well as other non-fibrous materials such as fillers andadhesives used to facilitate the original papermaking. Non-limitingexamples of suitable hardwood pulp fibers include eucalyptus and acacia.Non-limiting examples of suitable softwood pulp fibers include SouthernSoftwood Kraft (SSK) and Northern Softwood Kraft (NSK).

In addition to the various wood pulp fibers, other cellulosic fiberssuch as cotton linters, rayon, lyocell and bagasse can be used in thisinvention. Other sources of cellulose in the form of fibers or capableof being spun into fibers include grasses and grain sources.

In addition, trichomes, such as from “lamb's ear” plants, and seed hairscan also be utilized in the fibrous structures and/or sanitary tissueproducts of the present invention.

“Basis Weight” as used herein is the weight per unit area of a samplereported in lbs/3000 ft² or g/m² and is measured according to the BasisWeight Test Method described herein.

“Caliper” as used herein means the macroscopic thickness of a fibrousstructure. Caliper is measured according to the Caliper Test Methoddescribed herein.

“Density” as used herein is calculated as the quotient of the BasisWeight expressed in grams per square meter divided by the Caliperexpressed in microns.

“Machine Direction” or “MD” as used herein means the direction parallelto the flow of the fibrous structure through the fibrous structuremaking machine and/or sanitary tissue product manufacturing equipment.

“Cross Machine Direction” or “CD” as used herein means the directionparallel to the width of the fibrous structure making machine and/orsanitary tissue product manufacturing equipment and perpendicular to themachine direction.

“Ply” as used herein means an individual, integral fibrous structure.

“Plies” as used herein means two or more individual, integral fibrousstructures disposed in a substantially contiguous, face-to-facerelationship with one another, forming a multi-ply sanitary tissueproduct. It is also contemplated that an individual, integral fibrousstructure can effectively form a multi-ply sanitary tissue product, forexample, by being folded on itself.

“Textured surface pattern” with respect to a sanitary tissue product inaccordance with the present invention means herein a pattern ofprotrusions and/or depressions that is present on at least one surfaceof the sanitary tissue product. For example, the surface pattern maycomprise embossments.

“Embossed” as used herein with respect to a sanitary tissue productmeans a sanitary tissue product that has been subjected to a processwhich converts a smooth surfaced fibrous structure to a decorativesurface by replicating a design on one or more emboss rolls, which forma nip through which the fibrous structure passes. Embossed does notinclude creping, microcreping, printing or other processes that mayimpart a texture and/or decorative pattern to a fibrous structure.

“Line depression” as used herein means a depression in the surface of asanitary tissue product that comprises a continuous line that has anaspect ratio of greater than 1.5:1 and/or greater than 1.75:1 and/orgreater than 2:1 and/or greater than 5:1. In one example, the linedepression exhibits a length of at least 2 mm and/or at least 4 mmand/or at least 6 mm and/or at least 1 cm to about 10.16 cm and/or toabout 8 cm and/or to about 6 cm and/or to about 4 cm.

The line depressions of the present invention may be formed by lineembossing and/or wet forming, such as by wet molding and/or by using athrough-air-drying fabric and/or by using an imprintedthrough-air-drying fabric and/or by using a belt comprising a patternedresin.

In one example, the line depression is a discrete element. In anotherexample, the line depression defines the perimeter of a shape, such as acircle, ellipse, rectangle, or other rhombuses and/or triangles.

“Dot depression” as used herein means a depression that exhibits anaspect ratio of about 1:1. Non-limiting examples of dot depressions aredepressions that are shaped like circles, squares, ellipses, rectangles(dashes) and/or other rhombuses and/or triangles.

“Water-resistant” as it refers to a surface pattern or part thereofmeans that a pattern retains its structure and/or integrity after beingsaturated by water and the pattern is still visible to a consumer. Inone example, the depressions may be water-resistant.

Surface Patterns

FIG. 3 shows an example of a repeating design element 24 of a surfacepattern 12 of the present invention that can be imparted to a surface 14fibrous structures and/or sanitary tissue products comprising suchfibrous structures of the present invention. The surface pattern 12comprises a repeating design element 24. The repeating design element 24comprises a first set of lines 26 formed by a plurality ofvariable-sized discrete depressions 28. The variable-sized discretedepressions 28 are shown as dot depressions, but any suitable geometricshapes, such as dashes, triangles, ellipses, stars, and the like, may beused. The variable-sized discrete depressions 28 are arranged in aperiodic sequence along the length of one of the lines 26 based on thesize of the discrete depressions 28. Periodic sequence as used hereinmeans that a line 26 of variable-sized discrete depressions 28 is formedby line segments that contain an arrangement of variable-sized discretedepressions 28 that are sequential within one line segment, for exampleas follows:

Extra Large—Large—Medium—Small—Extra Small—Small—Medium—Large—ExtraLarge

Example 1

Extra Small—Small—Medium—Large—Extra Large—Large—Medium—Small—ExtraSmall

Example 2

Large—Medium—Small—Medium—Large—Medium—Small—Medium—Large

Example 3

For a given size of discrete depression, for example Extra Large inExample 2 above, one or more discrete depressions 28 may be present inthat position.

In one example, a line 26 of variable-sized discrete depressions 28 maycomprise one or more inflection points 30 along the length of the line26 and/or line set where the direction of the line 26 changes. Theinflection point 30 may actually be a discrete depression 28 and/or aplurality of discrete depressions 28 and/or even a space between twoadjacent discrete depressions 28. In Example 3 above, the inflectionpoints may be at the small discrete depressions, for example at aminimum-sized discrete depression within the line. In another example,the inflection point may be at the largest discrete depression, forexample the maximum-sized discrete depression within the line.

As shown in FIG. 3, the two lines 26 of the first set may be asymptoticto one another. In another example, the two lines 26 may be symmetricalto one another. In one case, the two lines 26 of the first set aremirror images of one another including the sizes and arrangements oftheir discrete depressions 28.

In one example, a geometric shape 32, such as a rhombus element, may bepositioned between the two lines 26 of the first set. The two lines 26of the first set may be oriented and/or arranged such that a node 20 isformed (by the combination of) between the two lines 26 of the firstset. The geometric shape 32 may be positioned within the node 20.

The geometric shape 32 comprises a largest dimension A and a smallestdimension B such that the geometric shape 32 exhibits an aspect ratio ofgreater than 1.25 and/or greater than 1.3 and/or greater than 1.4 and/orgreater than 1.5 and/or less than 3 and/or less than 2.5 and/or lessthan 2 and/or less than 1.9. In one example, the aspect ratio is fromabout 1.6 to about 1.8 and/or from about 1.7 to about 1.8. The two lines26 of the first set may be symmetrical along the geometric shape'slargest dimension A. The geometric shape 32 may comprise lineembossments and/or line moldings.

The two lines 26 of the first set may be curvilinear, such assinusoidal.

As shown in FIG. 4, the node 20 may comprise a two or more geometricshapes 32, such as a double rhombus element, for example an innerrhombus element. In one example, the aspect ratios of the two or moregeometric shapes 32 are similar, for example both greater than 1.25and/or greater than 1.3 and/or greater than 1.4 and/or greater than 1.5and/or less than 3 and/or less than 2.5 and/or less than 2 and/or lessthan 1.9. Further, the largest dimensions of the two or more geometricshapes 32 may be along the same axis.

In one example, the rhombus element comprises an inner rhombus elementhaving a larger dimension and smaller dimension that are different fromthe rhombus element's larger and smaller dimensions. In another example,the inner rhombus element exhibits a larger dimension and smallerdimension such that the inner rhombus element exhibits an aspect ratioof greater than 1.25. In even another example, the inner rhombuselement's larger dimension is parallel to the rhombus element's largerdimension.

As shown in FIG. 5, in another example of the repeating design element24, the repeating design element comprises a first set of lines 26 and asecond set of lines 34. The second set of lines 34, like the first setof lines 26, may be formed by a plurality of variable-sized discretedepressions 28, in one example, embossments, with all the samecharacteristics and arrangements (i.e., periodic sequence) as weredescribed above for the discrete depressions 28 of the lines 26 of thefirst set. In one example, the periodic sequence of the plurality ofvariable-sized discrete depressions 28 of the second set of lines 34 isdifferent from the periodic sequence of the plurality of variable-sizeddiscrete depressions 28 of the first set of lines 26. In one example,this difference in periodic sequence positions the smallest(minimum-sized discrete depression 28A of a line 26 of the first set inthe same corresponding position within its line as the maximum-sizeddiscrete depression 28B of a line 34 of the second set.

The lines 34 of the second set may be asymptotic to one another.Further, the lines 34 of the second set are spaced apart, for examplesubstantially equally distanced from one another, from the lines 26 ofthe first set along the length of the lines 26, 34. The lines 34 of thesecond set may be symmetrical to one another, for example along thegeometric shape's largest dimension A. In one case, the two lines 34 ofthe second set are minor images of one another including the sizes andarrangements of their discrete depressions 28.

In one example, a first set of lines are equally distanced from therhombus element's vertices in the rhombus element's smaller dimension.

The second set of lines 34 may form a node 36 that contains the node 20of the first set of lines 26.

The lines 34 of the second set may be curvilinear, such as sinusoidal.

In one example, the node 20 may comprise a text, such as a trademark,for example “Bounty” instead of a geometric shape 32.

In one example, the lines 26 of the first set and the lines 34 of thesecond set are substantially parallel to the cross machine direction ofthe fibrous structure and/or sanitary tissue product.

In addition to the first and second set of lines 26, 34, the repeatingdesign element 24 of the surface pattern 12 may comprise one or moreadditional sets of lines (not shown), which may be formed from aplurality of discrete depressions, for example like the first and secondset of lines.

Sanitary Tissue Products

As shown in FIGS. 6-9, examples of sanitary tissue products 10 of thepresent invention, such as paper towels, comprising a surface pattern 12according to the present invention.

The surface pattern 12 may be an emboss pattern, imparted by passing afibrous structure and/or sanitary tissue product made from a fibrousstructure through an embossing nip comprising at least one patternedembossing roll patterned to impart a surface pattern according to thepresent invention, and/or a water-resistant pattern (i.e., wet-moldedpattern), such as a patterned through-air-drying belt that is patternedto impart a surface pattern according to the present invention,typically imparted during the fibrous structure-making process.

In one example, the surface pattern 12 of the sanitary tissue product 10aids in the removal and/or dislodging soil more effectively than knownsanitary tissue products and/or the perception of removal and/ordislodging of soil more effectively than known sanitary tissue products.

The sanitary tissue products comprising a surface pattern of the presentinvention may be perceived by consumers of sanitary tissue products asbeing able to provide better cleaning of soil compared to sanitarytissue products comprising surface patterns not within the scope of thepresent invention.

Methods for Making Sanitary Tissue Products

The sanitary tissue products, for example paper towel products, of thepresent invention may be made by any suitable process known in the artso long as a surface pattern according to the present invention isimparted to a surface of the sanitary tissue products. The method may bea sanitary tissue product making process that uses a cylindrical dryersuch as a Yankee (a Yankee-process) or it may be a Yankeeless process asis used to make substantially uniform density (not differential density)and/or uncreped sanitary tissue products.

The sanitary tissue products of the present invention may be made usinga molding member. A “molding member” is a structural element that can beused as a support for an embryonic web comprising a plurality ofcellulosic fibers and a plurality of synthetic fibers, as well as aforming unit to form, or “mold,” a desired microscopical geometry of thesanitary tissue product of the present invention. The molding member maycomprise any element that has fluid-permeable areas and the ability toimpart a microscopical three-dimensional pattern to the structure beingproduced thereon, and includes, without limitation, single-layer andmulti-layer structures comprising a stationary plate, a belt, a wovenfabric (including Jacquard-type and the like woven patterns), a band,and a roll. In one example, the molding member is a deflection member.The molding member may comprise a surface pattern according to thepresent invention that is imparted to the sanitary tissue product duringthe sanitary tissue product making process.

A “reinforcing element” is a desirable (but not necessary) element insome embodiments of the molding member, serving primarily to provide orfacilitate integrity, stability, and durability of the molding membercomprising, for example, a resinous material. The reinforcing elementcan be fluid-permeable or partially fluid-permeable, may have a varietyof embodiments and weave patterns, and may comprise a variety ofmaterials, such as, for example, a plurality of interwoven yarns(including Jacquard-type and the like woven patterns), a felt, aplastic, other suitable synthetic material, or any combination thereof.

In one example of a method for making a sanitary tissue product of thepresent invention, the method comprises the step of contacting anembryonic fibrous web with a deflection member (molding member) suchthat at least one portion of the embryonic fibrous web is deflectedout-of-plane of another portion of the embryonic fibrous web. The phrase“out-of-plane” as used herein means that the sanitary tissue productcomprises a protuberance, such as a dome and/or line, or a cavity thatextends away from the plane of the sanitary tissue product. The moldingmember may comprise a through-air-drying belt, which comprises aresinous framework that imparts the surface pattern of the presentinvention to a surface of the sanitary tissue product and/or one or morefibrous structure making up the sanitary tissue product.

In another example the sanitary tissue product and/or fibrous structureused to make the sanitary tissue product may be subjected to anembossing operation that embosses the surface pattern of the presentinvention on a surface of the sanitary tissue product, for example papertowel, and/or fibrous structure. The embossing process createsout-of-plane deformation such that protuberances, such as a domes and/orlines, or corresponding cavities (based on what surface is viewed) thatextend away from the plane of the sanitary tissue product and/or fibrousstructure.

In another example of a method for making a sanitary tissue product ofthe present invention, the method comprises the steps of:

-   -   (a) providing a fibrous furnish comprising fibers, for example        pulp fibers, such as wood pulp fibers;    -   (b) depositing the fibrous furnish onto a foraminous member to        form an embryonic fibrous web;    -   (c) associating the embryonic fibrous web with a molding member        comprising a surface pattern such that the surface pattern;    -   (d) drying said embryonic fibrous web such that that the surface        pattern is imparted to the dried fibrous structure to form a        molded fibrous structure; and    -   (e) forming a sanitary tissue product from the molded fibrous        structure.

In another example of a method for making a sanitary tissue product ofthe present invention, the method comprises the steps of:

-   -   (a) providing a fibrous furnish comprising fibers, for example        pulp fibers, such as wood pulp fibers;    -   (b) depositing the fibrous furnish onto a foraminous member to        form an embryonic fibrous web; and    -   (c) drying said embryonic fibrous web such that that a dried        fibrous structure formed;    -   (d) subjecting the dried fibrous structure to an embossing        operation such that a surface pattern according to the present        invention is imparted to a surface of the dried fibrous        structure to form an embossed fibrous structure; and    -   (e) forming a sanitary tissue product from the embossed fibrous        structure.

In another example of a method for making a sanitary tissue product ofthe present invention, the method comprises the steps of:

-   -   (a) providing a fibrous structure; and    -   (b) imparting a surface pattern to the fibrous structure to        produce the sanitary tissue product.

In another example, the step of imparting a surface pattern to asanitary tissue product and/or fibrous structure comprises contacting amolding member comprising a surface pattern according to the presentinvention with a sanitary tissue product and/or fibrous structure suchthat the surface pattern is imparted to the sanitary tissue productand/or fibrous structure. The molding member may be a patternedthrough-air-drying belt that comprises a surface pattern.

In another example, the step of imparting a surface pattern to asanitary tissue product and/or fibrous structure comprises passing asanitary tissue product and/or fibrous structure through an embossingnip formed by at least one embossing roll comprising a surface patternaccording to the present invention such that the surface pattern isimparted to the sanitary tissue product and/or fibrous structure.

NON-LIMITING EXAMPLES Example 1

Examples of articles of manufacture, specifically fibrous structures;namely, paper towels for use in the comparative and inventive examplesbelow are produced utilizing a cellulosic pulp fiber furnish consistingof about 55% refined softwood furnish consisting of about 44% NorthernBleached Softwood Kraft (Bowater), 44% Northern Bleached Softwood Kraft(Celgar) and 12% Southern Bleached Softwood Kraft (Alabama RiverSoftwood, Weyerhaeuser); about 30% of unrefined hardwood EucalyptusBleached Kraft consisting of about 80% (Fibria) and 20% NBHK (Aspen)(Peace River); and about 15% of an unrefined furnish consisting of ablend of about 27% Northern Bleached Softwood Kraft (Bowater), 27%Northern Bleached Softwood Kraft (Celgar), 42% Eucalyptus Bleached Kraft(Fibria) and 7% Southern Bleached Kraft (Alabama River Softwood,Weyerhaeuser). The 55% refined softwood is refined as needed to maintaintarget wet burst at the reel. Any furnish preparation and refiningmethodology common to the papermaking industry can be utilized.

A 3% active solution Kymene 5221 is added to the refined softwood lineprior to an in-line static mixer and 1% active solution of Wickit 1285,an ethoxylated fatty alcohol available from Ashland Inc. is added to theunrefined Eucalyptus Bleached Kraft (Fibria) hardwood furnish. Theaddition levels are 21 and 1 lbs active/ton of paper, respectively.

The refined softwood and unrefined hardwood and unrefinedNBSK/SSK/Eucalyptus bleached kraft/NDHK thick stocks are then blendedinto a single thick stock line followed by addition of 1% activecarboxymethylcellulose (CMC-Finnfix) solution at 7 lbs active/ton ofpaper towel, and optionally, a softening agent may be added.

The thick stock is then diluted with white water at the inlet of a fanpump to a consistency of about 0.15% based on total weight of softwood,hardwood and simulated broke fiber. The diluted fiber slurry is directedto a non layered configuration headbox such that the wet web formed ontoa Fourdrinier wire (foraminous wire). Optionally, a finesretention/drainage aid may be added to the outlet of the fan pump.

Dewatering occurs through the Fourdrinier wire and is assisted bydeflector and vacuum boxes. The Fourdrinier wire is of a 5-shed, satinweave configuration having 87 machine-direction and 76 cross-directionmonofilaments per inch, respectively. The speed of the Fourdrinier wireis about 750 fpm (feet per minute).

The embryonic wet web is transferred from the Fourdrinier wire at afiber consistency of about 24% at the point of transfer, to a belt, suchas a patterned belt through-air-drying resin carrying fabric. In thepresent case, the speed of the patterned through-air-drying fabric isapproximately the same as the speed of the Fourdrinier wire. In anothercase, the embryonic wet web may be transferred to a patterned beltand/or fabric that is traveling slower, for example about 20% slowerthan the speed of the Fourdrinier wire (for example a wet moldingprocess).

Further de-watering is accomplished by vacuum assisted drainage untilthe web has a fiber consistency of about 30%.

While remaining in contact with the patterned belt, the web is pre-driedby air blow-through pre-dryers to a fiber consistency of about 65% byweight.

After the pre-dryers, the semi-dry web is transferred to a Yankee dryerand adhered to the surface of the Yankee dryer with a sprayed crepingadhesive. The creping adhesive is an aqueous dispersion with the activesconsisting of about 75% polyvinyl alcohol, and about 25% CREPETROL®R6390. Optionally a crepe aid consisting of CREPETROL® A3025 may beapplied. CREPETROL® R6390 and CREPETROL® A3025 are commerciallyavailable from Ashland Inc. (formerly Hercules Inc.). The crepingadhesive diluted to about 0.15% adhesive solids and delivered to theYankee surface at a rate of about 2# adhesive solids based on the dryweight of the web. The fiber consistency is increased to about 97%before the web is dry creped from the Yankee with a doctor blade.

In the present case, the doctor blade has a bevel angle of about 45° andis positioned with respect to the Yankee dryer to provide an impactangle of about 101° and the reel is run at a speed that is about 15%faster than the speed of the Yankee. In another case, the doctor blademay have a bevel angle of about 25° and be positioned with respect tothe Yankee dryer to provide an impact angle of about 81° and the reel isrun at a speed that is about 10% slower than the speed of the Yankee.The Yankee dryer is operated at a temperature of about 177° C. and aspeed of about 800 fpm. The fibrous structure is wound in a roll using asurface driven reel drum having a surface speed of about 656 feet perminute.

One parent roll of the fibrous structure may be unwound and embossedwith a surface texture as shown in FIGS. 3 to 9 and combined withanother parent roll of the fibrous structure not embossed to form atwo-ply paper towel product having a basis weight of about 45 to 54g/m².

Test Methods

Unless otherwise specified, all tests described herein including thosedescribed under the Definitions section and the following test methodsare conducted on samples that have been conditioned in a conditionedroom at a temperature of 73° F.±4° F. (about 23° C.±2.2° C.) and arelative humidity of 50%±10% for 2 hours prior to the test. All plasticand paper board packaging materials must be carefully removed from thepaper samples prior to testing. Discard any damaged product. All testsare conducted in such conditioned room.

Basis Weight Test Method

Basis weight of a sanitary tissue product sample is measured byselecting twelve (12) usable units (also referred to as sheets) of thesanitary tissue product and making two stacks of six (6) usable unitseach. Perforation must be aligned on the same side when stacking theusable units. A precision cutter is used to cut each stack into exactly8.89 cm×8.89 cm (3.5 in.×3.5 in.) squares. The two stacks of cut squaresare combined to make a basis weight pad of twelve (12) squares thick.The basis weight pad is then weighed on a top loading balance with aminimum resolution of 0.01 g. The top loading balance must be protectedfrom air drafts and other disturbances using a draft shield. Weights arerecorded when the readings on the top loading balance become constant.The Basis Weight is calculated as follows:

$\underset{({{lbs}\text{/}3000\mspace{14mu} {ft}^{2}})}{{Basis}\mspace{14mu} {Weight}} = \frac{{Weight}\mspace{14mu} {of}\mspace{14mu} {basis}\mspace{14mu} {weight}\mspace{14mu} {pad}\mspace{14mu} (g) \times 3000\mspace{14mu} {ft}^{2}}{\begin{matrix}{453.6\mspace{14mu} g\text{/}{lbs} \times 12( {{usable}\mspace{14mu} {units}} ) \times} \\\lbrack {12.25\mspace{14mu} {{{in}^{2}( {{Area}\mspace{14mu} {of}\mspace{14mu} {basis}\mspace{14mu} {weight}\mspace{14mu} {pad}} )}/144}\mspace{14mu} {in}^{2}} \rbrack\end{matrix}}$$\underset{({g\text{/}m^{2}})}{{Basis}\mspace{14mu} {Weight}} = \frac{{Weight}\mspace{14mu} {of}\mspace{14mu} {basis}\mspace{14mu} {weight}\mspace{14mu} {pad}\mspace{14mu} (g) \times 10,000\mspace{14mu} {cm}^{2}\text{/}m^{2}}{79.0321\mspace{14mu} {{cm}^{2}( {{Area}\mspace{14mu} {of}\mspace{14mu} {basis}\mspace{14mu} {weight}\mspace{14mu} {pad}} )} \times 12( {{usable}\mspace{14mu} {units}} )}$

Caliper Test Method

Caliper of a sanitary tissue product is measured by cutting five (5)samples of sanitary tissue product such that each cut sample is largerin size than a load foot loading surface of a VIR Electronic ThicknessTester Model II available from Thwing-Albert Instrument Company,Philadelphia, Pa. Typically, the load foot loading surface has acircular surface area of about 3.14 in². The sample is confined betweena horizontal flat surface and the load foot loading surface. The loadfoot loading surface applies a confining pressure to the sample of 15.5g/cm². The caliper of each sample is the resulting gap between the flatsurface and the load foot loading surface. The caliper is calculated asthe average caliper of the five samples. The result is reported inmillimeters (mm).

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application and any patent application or patent to which thisapplication claims priority or benefit thereof, is hereby incorporatedherein by reference in its entirety unless expressly excluded orotherwise limited. The citation of any document is not an admission thatit is prior art with respect to any invention disclosed or claimedherein or that it alone, or in any combination with any other referenceor references, teaches, suggests or discloses any such invention.Further, to the extent that any meaning or definition of a term in thisdocument conflicts with any meaning or definition of the same term in adocument incorporated by reference, the meaning or definition assignedto that term in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A sanitary tissue product comprising a surfacepattern having a repeating design element, wherein the repeating designelement contains a first rhombus element having larger dimension andsmaller dimension such that it exhibits an aspect ratio of greater than1.25, wherein the first rhombus element is positioned between a firstset of two lines formed by a plurality of variable-sized discretedepressions, wherein the variable-sized discrete depressions arearranged in a periodic sequence based on size of the discretedepressions, wherein the two lines are symmetrical to one another alongthe rhombus element's largest dimension.
 2. The sanitary tissue productaccording to claim 1 wherein the two lines of the first set arecurvilinear such that the combination of the two lines of the first setforms a first node within which the rhombus element is positioned. 3.The sanitary tissue product according to claim 1 wherein at least oneline of the first set comprises one or more inflection points along thelength of the line of the first set.
 4. The sanitary tissue productaccording to claim 3 wherein at least one of the inflection pointscomprises a minimum-sized discrete depression within the at least oneline of the first set.
 5. The sanitary tissue product according to claim3 wherein at least one of the inflection points comprises amaximum-sized discrete depression within the at least one line of thefirst set.
 6. The sanitary tissue product according to claim 1 whereinthe two lines of the first set are asymptotic to one another.
 7. Thesanitary tissue product according to claim 1 wherein the repeatingdesign element further comprises a second set of two lines formed by aplurality of variable-sized discrete depressions, wherein thevariable-sized discrete depressions are arranged in a periodic sequencebased on size of the discrete depressions, wherein the two lines of thesecond set are symmetrical to one another along the rhombus element'slargest dimension.
 8. The sanitary tissue product according to claim 7wherein the two lines of the second set are curvilinear such that thecombination of the two lines of the second set forms a second nodewithin which the first node formed by the combination of the two linesof the first set is positioned.
 9. The sanitary tissue product accordingto claim 7 wherein at least one line of the second set comprises one ormore inflection points along the length of the line of the second set.10. The sanitary tissue product according to claim 7 wherein the twolines of the second set of two lines are asymptotic to one another. 11.The sanitary tissue product according to claim 7 wherein the lines ofthe first set of two lines exhibit a periodic sequence that is differentfrom the lines of the second set of two lines.
 12. The sanitary tissueproduct according to claim 7 wherein the first and second set of linesare equally distanced from one another.
 13. The sanitary tissue productaccording to claim 7 wherein at least one line of the first setcomprises at least one inflection point comprising a minimum-sizeddiscrete depression and at least one line of the second set comprises atleast one inflection point comprising a maximum-sized discretedepression, wherein the minimum-sized discrete depression of the line ofthe first set is at a corresponding position within its line as is themaximum-sized discrete depression of the line of the second set.
 14. Thesanitary tissue product according to claim 1 wherein the first set oflines are equally distanced from the rhombus element's vertices in therhombus element's smaller dimension.
 15. The sanitary tissue productaccording to claim 1 wherein the rhombus element comprises an innerrhombus element having a larger dimension and smaller dimension that aredifferent from the rhombus element's larger and smaller dimensions. 16.The sanitary tissue product according to claim 15 wherein the innerrhombus element exhibits a larger dimension and smaller dimension suchthat the inner rhombus element exhibits an aspect ratio of greater than1.25.
 17. The sanitary tissue product according to claim 15 wherein theinner rhombus element's larger dimension is parallel to the rhombuselement's larger dimension.
 18. The sanitary tissue product according toclaim 1 wherein the discrete depressions are embossments.
 19. Thesanitary tissue product according to claim 1 wherein the discretedepressions are wet formed.
 20. The sanitary tissue product according toclaim 1 wherein the sanitary tissue product is a paper towel.